Extract of Scytonema bilaspurense NK13 strongly exhibits anticancer activities on cervical cancer HeLa cells

Cyanobacteria are new emerging sources of anticancer compounds with many lead structures for drug development. This study aimed to elucidate the anticancer activity of the crude extract of Scytonema bilaspurense NK13 on cervical cancer HeLa cells based on its ability to induce apoptotic inducements, arrest cell cycles and inhibit cell invasion. As a result, a number of cells treated with the NK13 extract (NK13E) entering apoptotic phases were 5.0-fold higher than that of negative control cells. Accordingly, the transcript levels of BAX, CASPASE-8, and CASPASE-3 in the NK13E-treated cells were up-regulated with 23.7-, 3.6- and 1.3-fold, respectively, higher than those in the negative control cells. Moreover, treatment with NK13E caused cell cycle arrest at the S phase in a p53-independent manner. Particularly, percentages of NK13E-treated cells in sub-G1, S, G2/M were 22.2%, 24.6% and 13.8%, while percentages of DMSO-treated-control cells in sub-G1, S, G2/M were 3.3%, 15.3% and 19.7%, respectively. Consistent with cell cycle arrest results, the expression levels of CDKN1A and CDNK2A in NK13E-treated cells were promoted to 26.6-folds and 5.6-folds higher than those of negative control cells, respectively. In addition, NK13E could also significantly inhibit invasion ability of the cells in vitro. This result was proven by up-regulating FAK/PI3K/AKT, along with down-regulating N-cadherin, which plays a crucial role in regulating the invasion activity of cancer cells. In conclusion, we suggest that the Scytonema bilaspurense NK13 strain is a potential source of precious compounds for developing new therapies for cervical cancer treatment.